JPH04155909A - Manufacture of solid electrolytic capacitor - Google Patents

Abstract

PURPOSE:To prevent a capacity from getting into an unstable condition due to splashes of solution by covering a valve metal foil of an element with another valve metal foil. CONSTITUTION:One end of a valve metal foil 2 in the longitudinal direction is coated with a protective valve metal foil 1 which prevents influences of splashes of solution from occurring. The ends of the valve metal foils 2 coated with the valve metal foils 1 are connected to a long side 3a of a rectangular metal sheet 3 at fixed intervals so that the valve metal foils 1, 2 may be at right angles with the side 3a. With a part 5 of the end of the valve metal foil 2 coated with the valve metal foil 1 being undone, a semiconductor layer 7 and conductor layer 8 are deposited in sequence on a part of the valve metal foils 1, 2 which is under a line 6. Then, the valve metal foils 1 and 2 are separated from each other to obtain a solid electrolytic capacitor element 10 which is composed of the valve metal foil 2. A lead wire is mounted to a part of the valve metal foil part of the element on which no semiconductor layer 7 is deposited and to a part on which the conductor layer 8 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing solid electrolytic capacitors that can be stably mass-produced with a desired capacity.

[Conventional technology]

BACKGROUND OF THE INVENTION In recent years, electronic devices have been becoming lighter and smaller, and all electrical components are required to be smaller.

In solid electrolytic capacitors, the capacity is derived from an internal element that has a semiconductor layer formed on a dielectric oxide film layer, but by reducing the dimensions of the internal element as much as possible, it is possible to meet the demand for miniaturization. I'm trying to respond.

However, as the dimensions of the internal elements become smaller, the liquid used to form the semiconductor layer splatters, making it impossible to stably manufacture solid electrolytic capacitors with the desired capacity. .

Silicone, polyamide,
A method of applying an insulating paint such as a fluororesin to a predetermined area to form an insulating resin film to prevent the liquid from adhering to the upper part due to splashing during the formation of a semiconductor layer (Japanese Patent Laid-Open No. 59-13
No. 2614) and the like have been proposed.

[Problem to be solved by the invention]- However, when applying insulating paint, if the viscosity of the paint is too high, it is difficult to form an insulating resin film, and if the viscosity is too low, the paint may seep into the coating. On the contrary, the problem arises that the capacitance of the manufactured element becomes unstable.

In particular, when forming insulating resin films for a large number of devices on an industrial scale, it becomes extremely difficult to control the viscosity of the insulating paint.

Therefore, instead of applying an insulating paint to form an insulating resin film, a method of attaching an adhesive resin tape may be considered, but the adhesion between the dielectric oxide film layer and the adhesive resin tape is difficult to achieve during the formation of the semiconductor layer. It is easily peeled off by a solvent during post-chemical formation to repair deterioration of the dielectric oxide film layer or when immersed in a conductive paste bath to form a conductive layer. In addition, insulating resin contains a large number of catalysts and various additives used during the production of insulating resin, which may be dissolved in post-forming solvents and conductive heaste solvents, adversely affecting the Funtensa element and impairing its reliability. There was some inconvenience.

The present invention has been made in view of the above circumstances, and prevents the capacitance from becoming unstable due to splashing of the liquid forming the semiconductor layer, and does not use insulating resin paint, etc. The purpose of the present invention is to provide a method for manufacturing solid electrolytic capacitors that is free from the effects of catalysts and various additives and is suitable for mass production.

[Means to solve the problem]

In the method for manufacturing a solid electrolytic capacitor of the present invention, a plurality of narrow rectangular valve metal layers 2 having one end in the longitudinal direction sandwiched by the valve metal layer 1 are replaced by a metal plate having at least one linear side. One end sandwiched by the valve metal layer 1 is connected and attached in parallel so as to be perpendicular to the one side of the valve metal layer 1.2, and a dielectric oxide film layer is formed on the surface of the valve metal layer 1.2. Then, after sequentially forming a semiconductor layer and a conductor layer except for one end side of the valve metal layer 1.2, the portion of the valve metal layer 1.2 where the semiconductor layer is not formed is used to form a valve. The solution to this problem was to include a step of cutting and separating the metal layers 1 and 2.

In this case, valve metal layers having a dielectric film formed on their surfaces may be used as the valve metal layers 1 and 2, and a semiconductor layer and a conductor layer may be sequentially formed thereon.

[Effect]

Since the method of the present invention has the above structure, the valve metal layer 2
One end of the valve is covered and protected by the valve metal layer 1, so that the influence of liquid splashing does not occur.

〔Example〕

1 to 5 show an embodiment of the method for manufacturing a solid electrolytic capacitor according to the present invention, and the reference numeral 1 in the figures indicates the effect of splashing of the liquid forming the dielectric layer. It is a protective rectangular valve metal layer that prevents. This valve metal layer 1
Thus, one longitudinal end of the narrow rectangular valve metal layer 2 is sandwiched and covered.

One end of the valve metal layer 1 that is sandwiched and covered by the valve metal layer 2 is attached to the long side 3a of the rectangular metal plate 3 so that the valve metal layer 1.2 is perpendicular to the side 3a. , are connected in parallel at a predetermined interval.

A dielectric oxide film layer 4 may be formed on the surface of the valve metal, or in this case, this operation may be omitted by using the valve metal layers 1 and 2 on which the dielectric oxide film layer 4 has been formed in advance. good.

Next, a semiconductor layer 7 and a conductor are sequentially applied to the valve metal layers 1 and 2 below the line 6, leaving a part (hereinafter referred to as the base) 5 on one end side sandwiched by the valve metal layer l. Layer 8 is laminated.

Either cut this at line 9, which is the part above line 6, or
Or, if the part connected to the metal plate 3 is separated,
The valve metal layers 1 and 2 are separated, and a solid electrolytic capacitor element (hereinafter referred to as element) 10 made of the valve metal layer 2 is obtained. Lead wires (not shown) are attached to the valve metal foil portions of these elements 10 where the semiconductor layer 7 is not formed and to the portions where the conductor layer 8 is formed.

As the valve metal layer 1.2 used in the present invention, any metal foil having a valve action such as aluminum, tantalum, niobium, titanium, or an alloy having these as a substrate can be used.

The surfaces of these valve metal layers 1 and 2 may be etched. As the etching method, a known method such as electrochemical etching may be used.

Furthermore, the valve metal layers 1 and 2 may have a dielectric oxide film layer 4 formed on their surfaces in advance.

It is important that the shape of the valve metal layer 1 that covers and sandwiches the valve metal layer 2 is a shape having at least two linear opposing sides, and that the width is larger than the width of the narrow rectangular valve metal layer 2. , especially rectangular ones are preferred. The valve metal layer 1 is
It is sufficient that the valve metal layer 2 covered and sandwiched therein has a width sufficient to prevent the semiconductor layer from creeping up from the end of the valve metal layer 2 during the formation of the semiconductor layer. Large ones are used.

Furthermore, the size of the portion of the valve metal layer 1 that covers the valve metal layer 2 is as follows:
The capacitance varies depending on the capacitance of the capacitor to be manufactured, and in order to obtain a certain desired capacitance, the valve metal layer 1 is covered except for the portion where the semiconductor layer is to be formed.

Further, as a method of covering the valve metal layer 2 with the valve metal layer 1, a method of covering the valve metal layer 2 from the front and back with two valve metal layers 1, and
There are methods of folding one valve metal layer 1 and covering the valve metal layer 2, and any of these methods may be used.

The metal plate 3 to which the valve metal layer 2 sandwiched and coated with the valve metal layer l is connected must have the function and strength to connect the valve metal layer, and must not bend even when the valve metal layer is connected. There are no particular limitations, and examples include stainless steel, steel, copper, iron, and aluminum.

The metal plate 3 only needs to have one linear side of a predetermined length, but usually a rectangular one is used, and its length is determined by the width of the valve metal layer 1, the number of connected plates, and the spacing. The thickness of the metal plate 3 is increased if it is long in order to prevent deflection due to the above-mentioned required length, but it is usually 0.1a+m to several inches thick.
A material with a thickness of .

The method of connecting the metal plate 3 to the valve metal layer 1 and the valve metal layer 2 includes welding, soldering, bolting, groove welding, etc.
Conventionally known electrical and mechanical methods are used.

In the present invention, the dielectric oxide film layer (hereinafter referred to as oxide film layer) 4 formed on the valve metal seedling soil may be an oxide film layer of the valve metal itself, or may be an oxide film layer provided on the valve metal seedling soil.
Although an oxide film layer made of an oxide of another dielectric substance may be used, an oxide film layer made of an oxide of the valve metal itself is particularly preferable. In any of the above cases, a conventionally known method can be used to form the oxide film layer 4. For example, when aluminum is used as the valve metal layer, the surface of the aluminum foil is electrochemically etched, and an aqueous solution of boric acid and ammonium borate is added.
When electrochemically treated in an aqueous solution of phosphoric acid and ammonium phosphate, an aqueous ammonium adipate solution, or an aqueous solution of oxalic acid and ammonium oxalate, an oxide film layer made of an alumina electrolyte is formed on the aluminum foil.

The composition and formation method of the semiconductor layer 7 used in the present invention are not particularly limited; A method in which the layer is formed by chemical deposition (
It is preferable to use a method of forming a semiconductor layer containing lead dioxide as a main component by electrochemical deposition (Japanese Patent Application Laid-open No. 62-185307).

The conductor layer 8 formed on the surface of the semiconductor layer 7 is formed by a known method such as applying and solidifying a conductive paste, plating, metal vapor deposition, or laminating a heat-resistant conductive resin film.

As the conductive paste, any known paste containing metal powder or conductive polymer as a main component can be used.

The element 10 made as described above and having lead wires attached thereto can be molded into a resin mold, a resin case, a metal exterior case, resin dumping, exterior with a laminate film, etc. to obtain a general-purpose capacitor product for various uses.

In the above explanation, even if the element IO is separated by three metal plates, the lead wires are connected and the lead wires are connected, and the element 10 is separated by three or one metal plates, the outer part is further removed. The metal plates may be separated after applying this process.

[Example 1] A double-notched aluminum foil (approximately 45μF/cm'') with a length of 101m, a width of 7III11, and a thickness of 0.1mm was folded in half at the center to make a length of 5III+, while a length of 8m and a width of 3 Insert one longitudinal end of a 1mm thick aluminum elatin chemical foil (approximately 45μF/cm") all the way to the end, and align the center lines of both foils to match. We prepared 40 pieces. Next, thickness 0゜51, width 2
The ends of the sandwiching portions of the 40 chemically formed foils were connected to a stainless steel metal plate measuring 0 m5 and 400 t+e in length (with the other end aligned at an interval of 2 mm) by spot welding.

A 6 mm portion from the other end of the chemically formed foil was immersed in phosphorous liquor and an aqueous ammonium phosphate solution to refinish. Furthermore, a portion 3 mm from the other end of the chemically formed foil was immersed in a mixture of an aqueous solution of 2.4 mol/Q of lead acetate trihydrate and an aqueous solution of ammonium persulfate of 4 mol/Q.
C, react for 1 hour, lead dioxide 25wt%, lead sulfate 75%
A semiconductor layer consisting of wt% was formed. This was followed by post-chemical conversion using the above solution.

After repeating this semiconductor layer formation and post-chemical forming operation twice, the semiconductor layer is sequentially immersed in a carbon paste tank and a silver paste tank.
A conductor layer was formed on the semiconductor layer.

Then, a portion of 5 InLll was cut from the other end to produce a device. At this stage, all the elements had a portion based on the chemically formed foil with a width of 3 mm, and the boundary with the portion on which the semiconductor layer was not formed was clear.

These elements were prepared with a width of 3 mm and a length of 5 mm.

゛ Two iron-based foils with a thickness of 0.1 am were placed on the parts of the above element where only the conductor layer and dielectric layer were present, and the former was applied with silver paste and the latter with spot welding. A capacitor was fabricated by mechanically connecting them and sealing them with resin.

The characteristic values of these 40 capacitors were measured, and their average values and variations are shown in Table 1.

In Table 1, however, the value H100 at *1207 is set /l ***tOV [Effects of the Invention] As explained above, according to the method for manufacturing a solid electrolytic capacitor according to the present invention, especially the semiconductor layer Since the valve metal foil of the element is held so as to be covered and sandwiched by another valve metal foil during the formation process, the capacity is stable, workability is good, and it is suitable for mass production. Furthermore, the manufactured capacitor has advantages such as excellent characteristics.

[Brief explanation of the drawing]

Figures 1 to 5 show an embodiment of the method of the present invention, and Figure 1 shows a state in which a valve metal foil, a part of which is sandwiched between protective valve metal foils, is connected to a metal plate. A plan view, FIG. 2 is a view taken along the line ■-■ in FIG. 1, FIG. 3 is a diagram showing the position where the semiconductor layer is provided on the valve metal foil and the cutting position, and FIG. 4 is a view taken along the line ■-■ in FIG. A sectional view taken along the line, and FIG. 5 is a perspective view of a solid electrolytic capacitor element manufactured by the above procedure. l... Valve metal foil (for protection), 2... Valve metal foil, 3...
...Metal plate, 3a...Longer side, 4...Dielectric oxide film layer (oxide film), end...Part of one end side (base, 6
... line, 7 ... semiconductor layer, 8 ... conductor layer, 9 ...
- Line, 10...Solid electrolytic capacitor element (element).

Claims (2)

[Claims] (1) A plurality of narrow rectangular valve metal foils 2 with one longitudinal end held between the valve metal foils 1 are placed at right angles to the one side of the metal plate 3 having at least one linear side. One end sandwiched by the valve metal foils 1 is connected in parallel so that a dielectric oxide film layer is formed on the surfaces of these valve metal foils 1 and 2, and then the valve metal foils 1 and 2 are connected in parallel. 2
After sequentially forming a semiconductor layer and a conductor layer except for one end side, cutting and separating the valve metal foils 1 and 2 at the portions where the semiconductor layer is not formed. A method for manufacturing a solid electrolytic capacitor, comprising: (2) As the valve metal foils 1 and 2, use the valve metal foils 1 and 2 on which a dielectric oxide film layer is formed on the surface, and sequentially leave one end side of the valve metal foils 1 and 2 The method for manufacturing a solid electrolytic capacitor according to claim 1, wherein a semiconductor layer and a conductor layer are formed.